1 files changed, 655 insertions, 0 deletions

diff --git a/http-backend.c b/http-backend.c
new file mode 100644
index 0000000..f729488
--- /dev/null
+++ b/http-backend.c
@@ -0,0 +1,655 @@
+#include "cache.h"
+#include "refs.h"
+#include "pkt-line.h"
+#include "object.h"
+#include "tag.h"
+#include "exec_cmd.h"
+#include "run-command.h"
+#include "string-list.h"
+
+static const char content_type[] = "Content-Type";
+static const char content_length[] = "Content-Length";
+static const char last_modified[] = "Last-Modified";
+static int getanyfile = 1;
+
+static struct string_list *query_params;
+
+struct rpc_service {
+	const char *name;
+	const char *config_name;
+	signed enabled : 2;
+};
+
+static struct rpc_service rpc_service[] = {
+	{ "upload-pack", "uploadpack", 1 },
+	{ "receive-pack", "receivepack", -1 },
+};
+
+static int decode_char(const char *q)
+{
+	int i;
+	unsigned char val = 0;
+	for (i = 0; i < 2; i++) {
+		unsigned char c = *q++;
+		val <<= 4;
+		if (c >= '0' && c <= '9')
+			val += c - '0';
+		else if (c >= 'a' && c <= 'f')
+			val += c - 'a' + 10;
+		else if (c >= 'A' && c <= 'F')
+			val += c - 'A' + 10;
+		else
+			return -1;
+	}
+	return val;
+}
+
+static char *decode_parameter(const char **query, int is_name)
+{
+	const char *q = *query;
+	struct strbuf out;
+
+	strbuf_init(&out, 16);
+	do {
+		unsigned char c = *q;
+
+		if (!c)
+			break;
+		if (c == '&' || (is_name && c == '=')) {
+			q++;
+			break;
+		}
+
+		if (c == '%') {
+			int val = decode_char(q + 1);
+			if (0 <= val) {
+				strbuf_addch(&out, val);
+				q += 3;
+				continue;
+			}
+		}
+
+		if (c == '+')
+			strbuf_addch(&out, ' ');
+		else
+			strbuf_addch(&out, c);
+		q++;
+	} while (1);
+	*query = q;
+	return strbuf_detach(&out, NULL);
+}
+
+static struct string_list *get_parameters(void)
+{
+	if (!query_params) {
+		const char *query = getenv("QUERY_STRING");
+
+		query_params = xcalloc(1, sizeof(*query_params));
+		while (query && *query) {
+			char *name = decode_parameter(&query, 1);
+			char *value = decode_parameter(&query, 0);
+			struct string_list_item *i;
+
+			i = string_list_lookup(name, query_params);
+			if (!i)
+				i = string_list_insert(name, query_params);
+			else
+				free(i->util);
+			i->util = value;
+		}
+	}
+	return query_params;
+}
+
+static const char *get_parameter(const char *name)
+{
+	struct string_list_item *i;
+	i = string_list_lookup(name, get_parameters());
+	return i ? i->util : NULL;
+}
+
+__attribute__((format (printf, 2, 3)))
+static void format_write(int fd, const char *fmt, ...)
+{
+	static char buffer[1024];
+
+	va_list args;
+	unsigned n;
+
+	va_start(args, fmt);
+	n = vsnprintf(buffer, sizeof(buffer), fmt, args);
+	va_end(args);
+	if (n >= sizeof(buffer))
+		die("protocol error: impossibly long line");
+
+	safe_write(fd, buffer, n);
+}
+
+static void http_status(unsigned code, const char *msg)
+{
+	format_write(1, "Status: %u %s\r\n", code, msg);
+}
+
+static void hdr_str(const char *name, const char *value)
+{
+	format_write(1, "%s: %s\r\n", name, value);
+}
+
+static void hdr_int(const char *name, uintmax_t value)
+{
+	format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
+}
+
+static void hdr_date(const char *name, unsigned long when)
+{
+	const char *value = show_date(when, 0, DATE_RFC2822);
+	hdr_str(name, value);
+}
+
+static void hdr_nocache(void)
+{
+	hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
+	hdr_str("Pragma", "no-cache");
+	hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
+}
+
+static void hdr_cache_forever(void)
+{
+	unsigned long now = time(NULL);
+	hdr_date("Date", now);
+	hdr_date("Expires", now + 31536000);
+	hdr_str("Cache-Control", "public, max-age=31536000");
+}
+
+static void end_headers(void)
+{
+	safe_write(1, "\r\n", 2);
+}
+
+__attribute__((format (printf, 1, 2)))
+static NORETURN void not_found(const char *err, ...)
+{
+	va_list params;
+
+	http_status(404, "Not Found");
+	hdr_nocache();
+	end_headers();
+
+	va_start(params, err);
+	if (err && *err)
+		vfprintf(stderr, err, params);
+	va_end(params);
+	exit(0);
+}
+
+__attribute__((format (printf, 1, 2)))
+static NORETURN void forbidden(const char *err, ...)
+{
+	va_list params;
+
+	http_status(403, "Forbidden");
+	hdr_nocache();
+	end_headers();
+
+	va_start(params, err);
+	if (err && *err)
+		vfprintf(stderr, err, params);
+	va_end(params);
+	exit(0);
+}
+
+static void select_getanyfile(void)
+{
+	if (!getanyfile)
+		forbidden("Unsupported service: getanyfile");
+}
+
+static void send_strbuf(const char *type, struct strbuf *buf)
+{
+	hdr_int(content_length, buf->len);
+	hdr_str(content_type, type);
+	end_headers();
+	safe_write(1, buf->buf, buf->len);
+}
+
+static void send_local_file(const char *the_type, const char *name)
+{
+	const char *p = git_path("%s", name);
+	size_t buf_alloc = 8192;
+	char *buf = xmalloc(buf_alloc);
+	int fd;
+	struct stat sb;
+
+	fd = open(p, O_RDONLY);
+	if (fd < 0)
+		not_found("Cannot open '%s': %s", p, strerror(errno));
+	if (fstat(fd, &sb) < 0)
+		die_errno("Cannot stat '%s'", p);
+
+	hdr_int(content_length, sb.st_size);
+	hdr_str(content_type, the_type);
+	hdr_date(last_modified, sb.st_mtime);
+	end_headers();
+
+	for (;;) {
+		ssize_t n = xread(fd, buf, buf_alloc);
+		if (n < 0)
+			die_errno("Cannot read '%s'", p);
+		if (!n)
+			break;
+		safe_write(1, buf, n);
+	}
+	close(fd);
+	free(buf);
+}
+
+static void get_text_file(char *name)
+{
+	select_getanyfile();
+	hdr_nocache();
+	send_local_file("text/plain", name);
+}
+
+static void get_loose_object(char *name)
+{
+	select_getanyfile();
+	hdr_cache_forever();
+	send_local_file("application/x-git-loose-object", name);
+}
+
+static void get_pack_file(char *name)
+{
+	select_getanyfile();
+	hdr_cache_forever();
+	send_local_file("application/x-git-packed-objects", name);
+}
+
+static void get_idx_file(char *name)
+{
+	select_getanyfile();
+	hdr_cache_forever();
+	send_local_file("application/x-git-packed-objects-toc", name);
+}
+
+static int http_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(var, "http.getanyfile")) {
+		getanyfile = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!prefixcmp(var, "http.")) {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
+			struct rpc_service *svc = &rpc_service[i];
+			if (!strcmp(var + 5, svc->config_name)) {
+				svc->enabled = git_config_bool(var, value);
+				return 0;
+			}
+		}
+	}
+
+	/* we are not interested in parsing any other configuration here */
+	return 0;
+}
+
+static struct rpc_service *select_service(const char *name)
+{
+	struct rpc_service *svc = NULL;
+	int i;
+
+	if (prefixcmp(name, "git-"))
+		forbidden("Unsupported service: '%s'", name);
+
+	for (i = 0; i < ARRAY_SIZE(rpc_service); i++) {
+		struct rpc_service *s = &rpc_service[i];
+		if (!strcmp(s->name, name + 4)) {
+			svc = s;
+			break;
+		}
+	}
+
+	if (!svc)
+		forbidden("Unsupported service: '%s'", name);
+
+	if (svc->enabled < 0) {
+		const char *user = getenv("REMOTE_USER");
+		svc->enabled = (user && *user) ? 1 : 0;
+	}
+	if (!svc->enabled)
+		forbidden("Service not enabled: '%s'", svc->name);
+	return svc;
+}
+
+static void inflate_request(const char *prog_name, int out)
+{
+	z_stream stream;
+	unsigned char in_buf[8192];
+	unsigned char out_buf[8192];
+	unsigned long cnt = 0;
+	int ret;
+
+	memset(&stream, 0, sizeof(stream));
+	ret = inflateInit2(&stream, (15 + 16));
+	if (ret != Z_OK)
+		die("cannot start zlib inflater, zlib err %d", ret);
+
+	while (1) {
+		ssize_t n = xread(0, in_buf, sizeof(in_buf));
+		if (n <= 0)
+			die("request ended in the middle of the gzip stream");
+
+		stream.next_in = in_buf;
+		stream.avail_in = n;
+
+		while (0 < stream.avail_in) {
+			int ret;
+
+			stream.next_out = out_buf;
+			stream.avail_out = sizeof(out_buf);
+
+			ret = inflate(&stream, Z_NO_FLUSH);
+			if (ret != Z_OK && ret != Z_STREAM_END)
+				die("zlib error inflating request, result %d", ret);
+
+			n = stream.total_out - cnt;
+			if (write_in_full(out, out_buf, n) != n)
+				die("%s aborted reading request", prog_name);
+			cnt += n;
+
+			if (ret == Z_STREAM_END)
+				goto done;
+		}
+	}
+
+done:
+	inflateEnd(&stream);
+	close(out);
+}
+
+static void run_service(const char **argv)
+{
+	const char *encoding = getenv("HTTP_CONTENT_ENCODING");
+	const char *user = getenv("REMOTE_USER");
+	const char *host = getenv("REMOTE_ADDR");
+	char *env[3];
+	struct strbuf buf = STRBUF_INIT;
+	int gzipped_request = 0;
+	struct child_process cld;
+
+	if (encoding && !strcmp(encoding, "gzip"))
+		gzipped_request = 1;
+	else if (encoding && !strcmp(encoding, "x-gzip"))
+		gzipped_request = 1;
+
+	if (!user || !*user)
+		user = "anonymous";
+	if (!host || !*host)
+		host = "(none)";
+
+	memset(&env, 0, sizeof(env));
+	strbuf_addf(&buf, "GIT_COMMITTER_NAME=%s", user);
+	env[0] = strbuf_detach(&buf, NULL);
+
+	strbuf_addf(&buf, "GIT_COMMITTER_EMAIL=%s@http.%s", user, host);
+	env[1] = strbuf_detach(&buf, NULL);
+	env[2] = NULL;
+
+	memset(&cld, 0, sizeof(cld));
+	cld.argv = argv;
+	cld.env = (const char *const *)env;
+	if (gzipped_request)
+		cld.in = -1;
+	cld.git_cmd = 1;
+	if (start_command(&cld))
+		exit(1);
+
+	close(1);
+	if (gzipped_request)
+		inflate_request(argv[0], cld.in);
+	else
+		close(0);
+
+	if (finish_command(&cld))
+		exit(1);
+	free(env[0]);
+	free(env[1]);
+	strbuf_release(&buf);
+}
+
+static int show_text_ref(const char *name, const unsigned char *sha1,
+	int flag, void *cb_data)
+{
+	struct strbuf *buf = cb_data;
+	struct object *o = parse_object(sha1);
+	if (!o)
+		return 0;
+
+	strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
+	if (o->type == OBJ_TAG) {
+		o = deref_tag(o, name, 0);
+		if (!o)
+			return 0;
+		strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
+	}
+	return 0;
+}
+
+static void get_info_refs(char *arg)
+{
+	const char *service_name = get_parameter("service");
+	struct strbuf buf = STRBUF_INIT;
+
+	hdr_nocache();
+
+	if (service_name) {
+		const char *argv[] = {NULL /* service name */,
+			"--stateless-rpc", "--advertise-refs",
+			".", NULL};
+		struct rpc_service *svc = select_service(service_name);
+
+		strbuf_addf(&buf, "application/x-git-%s-advertisement",
+			svc->name);
+		hdr_str(content_type, buf.buf);
+		end_headers();
+
+		packet_write(1, "# service=git-%s\n", svc->name);
+		packet_flush(1);
+
+		argv[0] = svc->name;
+		run_service(argv);
+
+	} else {
+		select_getanyfile();
+		for_each_ref(show_text_ref, &buf);
+		send_strbuf("text/plain", &buf);
+	}
+	strbuf_release(&buf);
+}
+
+static void get_info_packs(char *arg)
+{
+	size_t objdirlen = strlen(get_object_directory());
+	struct strbuf buf = STRBUF_INIT;
+	struct packed_git *p;
+	size_t cnt = 0;
+
+	select_getanyfile();
+	prepare_packed_git();
+	for (p = packed_git; p; p = p->next) {
+		if (p->pack_local)
+			cnt++;
+	}
+
+	strbuf_grow(&buf, cnt * 53 + 2);
+	for (p = packed_git; p; p = p->next) {
+		if (p->pack_local)
+			strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
+	}
+	strbuf_addch(&buf, '\n');
+
+	hdr_nocache();
+	send_strbuf("text/plain; charset=utf-8", &buf);
+	strbuf_release(&buf);
+}
+
+static void check_content_type(const char *accepted_type)
+{
+	const char *actual_type = getenv("CONTENT_TYPE");
+
+	if (!actual_type)
+		actual_type = "";
+
+	if (strcmp(actual_type, accepted_type)) {
+		http_status(415, "Unsupported Media Type");
+		hdr_nocache();
+		end_headers();
+		format_write(1,
+			"Expected POST with Content-Type '%s',"
+			" but received '%s' instead.\n",
+			accepted_type, actual_type);
+		exit(0);
+	}
+}
+
+static void service_rpc(char *service_name)
+{
+	const char *argv[] = {NULL, "--stateless-rpc", ".", NULL};
+	struct rpc_service *svc = select_service(service_name);
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
+	check_content_type(buf.buf);
+
+	hdr_nocache();
+
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "application/x-git-%s-result", svc->name);
+	hdr_str(content_type, buf.buf);
+
+	end_headers();
+
+	argv[0] = svc->name;
+	run_service(argv);
+	strbuf_release(&buf);
+}
+
+static NORETURN void die_webcgi(const char *err, va_list params)
+{
+	char buffer[1000];
+
+	http_status(500, "Internal Server Error");
+	hdr_nocache();
+	end_headers();
+
+	vsnprintf(buffer, sizeof(buffer), err, params);
+	fprintf(stderr, "fatal: %s\n", buffer);
+	exit(0);
+}
+
+static char* getdir(void)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *pathinfo = getenv("PATH_INFO");
+	char *root = getenv("GIT_PROJECT_ROOT");
+	char *path = getenv("PATH_TRANSLATED");
+
+	if (root && *root) {
+		if (!pathinfo || !*pathinfo)
+			die("GIT_PROJECT_ROOT is set but PATH_INFO is not");
+		if (daemon_avoid_alias(pathinfo))
+			die("'%s': aliased", pathinfo);
+		strbuf_addstr(&buf, root);
+		if (buf.buf[buf.len - 1] != '/')
+			strbuf_addch(&buf, '/');
+		if (pathinfo[0] == '/')
+			pathinfo++;
+		strbuf_addstr(&buf, pathinfo);
+		return strbuf_detach(&buf, NULL);
+	} else if (path && *path) {
+		return xstrdup(path);
+	} else
+		die("No GIT_PROJECT_ROOT or PATH_TRANSLATED from server");
+	return NULL;
+}
+
+static struct service_cmd {
+	const char *method;
+	const char *pattern;
+	void (*imp)(char *);
+} services[] = {
+	{"GET", "/HEAD$", get_text_file},
+	{"GET", "/info/refs$", get_info_refs},
+	{"GET", "/objects/info/alternates$", get_text_file},
+	{"GET", "/objects/info/http-alternates$", get_text_file},
+	{"GET", "/objects/info/packs$", get_info_packs},
+	{"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
+	{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
+	{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
+
+	{"POST", "/git-upload-pack$", service_rpc},
+	{"POST", "/git-receive-pack$", service_rpc}
+};
+
+int main(int argc, char **argv)
+{
+	char *method = getenv("REQUEST_METHOD");
+	char *dir;
+	struct service_cmd *cmd = NULL;
+	char *cmd_arg = NULL;
+	int i;
+
+	git_extract_argv0_path(argv[0]);
+	set_die_routine(die_webcgi);
+
+	if (!method)
+		die("No REQUEST_METHOD from server");
+	if (!strcmp(method, "HEAD"))
+		method = "GET";
+	dir = getdir();
+
+	for (i = 0; i < ARRAY_SIZE(services); i++) {
+		struct service_cmd *c = &services[i];
+		regex_t re;
+		regmatch_t out[1];
+
+		if (regcomp(&re, c->pattern, REG_EXTENDED))
+			die("Bogus regex in service table: %s", c->pattern);
+		if (!regexec(&re, dir, 1, out, 0)) {
+			size_t n;
+
+			if (strcmp(method, c->method)) {
+				const char *proto = getenv("SERVER_PROTOCOL");
+				if (proto && !strcmp(proto, "HTTP/1.1"))
+					http_status(405, "Method Not Allowed");
+				else
+					http_status(400, "Bad Request");
+				hdr_nocache();
+				end_headers();
+				return 0;
+			}
+
+			cmd = c;
+			n = out[0].rm_eo - out[0].rm_so;
+			cmd_arg = xmalloc(n);
+			memcpy(cmd_arg, dir + out[0].rm_so + 1, n-1);
+			cmd_arg[n-1] = '\0';
+			dir[out[0].rm_so] = 0;
+			break;
+		}
+		regfree(&re);
+	}
+
+	if (!cmd)
+		not_found("Request not supported: '%s'", dir);
+
+	setup_path();
+	if (!enter_repo(dir, 0))
+		not_found("Not a git repository: '%s'", dir);
+
+	git_config(http_config, NULL);
+	cmd->imp(cmd_arg);
+	return 0;
+}